(19)

(11)

EP 0 333 762 A1

(12)

(43) Date of publication: 27.09.1989 Bulletin 1989/39 (21) Application number: 88900193.0 (22) Date of filing: 25.11.1987

(51) International Patent Classification (IPC):  B01D 25/ 172( . ) (86) International application number: PCT/US1987/003134 (87) International publication number: WO 1988/003832 (02.06.1988 Gazette 1988/12)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 28.11.1986 US 19860936091 (71) Applicant: ENVIROTECH CORPORATION Menlo Park California 94025 (US)	(72) Inventor: DAVIS, Steven, S. Farmington, UT 84025 (US) (74) Representative: Buzzi, Franco, et al  c/o Jacobacci-Casetta & Perani S.p.A. Via Alfieri, 17 I-10121 Torino I-10121 Torino (IT)